Adjustable eccentric



P. C. MALMSTEN ADJUSTABLE ECCENTRIC Jan. 29, 1952 3 Sheets-Sheet 1 Filed June 12, 1946 INVENTOR. Ffi/Zjv C why/ 2 Jan. 29, 1952 P. c. MALMSTEN 2,583,364

ADJUSTABLE ECCENTRIC I 7 Filed June 12, 1946 5 Sheets-Sheet 2 Jan. 29, 19 52 P. c. MALMSTEN 2,533,364

ADJUSTABLE ECCENTRIC Filed June 12, 1946 5 Sheets-Sheet 3 INVENTOR.

Phil 1 C/Kczlmszefl Patentecl Jan. 29 I952 ADJUSTABLE ECCENTRIC Philip C. Malmsten, Milwaukee, assignor to t A. O. Smith Corporation, Milwaukee, Wis., a

corporation of New York Application June 12, 1946, Serial No. 676,268

This invention relates to an adjustable eccentric and has particular reference to an adjustment which regulates the rotation of the stoker feed screw to obtain different rates of feed of coal to the furnace.

One object of the invention is to provide a readily accessible and simple adjustment for regulating the stroke of the feed screw of a stoker.

Another object is to provide an intermittently driven stoker feed screw with a plurality of adjustments of the stroke for different feedings of coal as may he demanded by the weather or other operating conditions.

These and other objects of the invention will appear hereinafter in connection with the following description of an embodiment of the invention illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevational view of a stoker power unit assembly with the connecting rod disconnected from the clutch and parts broken away and sectioned;

Fig. 2 is an elevational view of the end of a stcker with part of the casing broken away and showing the connecting rod secured to the clutch;

Fig. 3 is a section taken on line 3--3 of Fig. 2;

Fig. 4 is a diagrammatic view of the setting for the shortest stroke;

Fig. 5 is a similar view of the setting for an intermediate stroke; and

Fig. 6 is a diagrammatic view of the setting for the longest stroke.

The drawings, in general, show a hopper l of a stoker to the one side of the lower outer portion of which is secured the drive unit comprising the fan 2, the motor 3 and the transmission mechanism 4. The transmission mechanism 4 is driven off from the rear end of the drive shaft 5 of motor 3 and intermittently rotates the stoker feed screw 6 through the connecting rod 1 and the clutch unit 8 to feed coal to the furnace, not shown, from the bottom of hopper I through which feed screw 6 extends. The length of the stroke of rod 1 determines the rate of feed of screw 6 and the invention is particularly directed to apparatus for regulating the stroke of rod 1 and the feed rate.

The transmission mechanism 4, in general, comprises the gears 9 and the crank shaft H) which is driven by gears 9 from the motor drive shaft 5 at a reduced speed. Shaft l extends parallel to shaft and projects from the rear end of the housing of transmission mechanism 4.

The crank H of crank shaft I0 is offset from the shaft and is located outside the rear housing 1 Claim. (01. 74-57 1) of transmission mechanism 4 within the bearing l2. The bearing I2 is press fitted inside the crank end of the connecting rod 1 which is formed of two corresponding half members longitudinally welded together.

The bearing I2 is eccentric in that the center of the'bearing is offset from the center of the crank H which is disposed within the eccentric dinally through the inner bearing surface thereof.

Thecrank II has a semi-circular groove l5 which extends longitudinally in the outer peripheryof the crank. Groove I5 is complementary to each of grooves l4 and when bearing I2 is rotated, as will be described, to place groove IS in registry with one of the grooves I4, a longitudinal aperture is formed therewith between the crank and race l3 to receive the pin l6. Pin l6 locks the crank and bearing together for rotation and actuation of rod 1.

The cover or dial plate l l is located over the outer end [8 of transmisison shaft H] which projects outwardly from crank ll. Plate [1, which corresponds in diameter to bearing I2, is secured to the inner race l3 of bearing [2 by screws I!) so that race l3 and plate I! rotate together. l r 7 Plate I! has aplurality of apertures 2|] in the face thereof. Apertures 20 correspond in number and are each horizontally aligned with a groove I4 in bearing race 13. The center of plate I! is offset from the center of crank II or end l8 of transmission shaft [0 in the same manner as the center of bearing 12 is offset from the center of the crank. I

.The locking pin l6 previously described extends through one of the apertures 20 and thence into the aperture between crank H and bearing race 13 which is formed when one of the semicirculargrooves I4 of the race registers with the semi-circular groove [5 of the crank. Pin I6 is enlarged at the outer end 2| and may be knurled to provide for grasping by the operator for ready insertion and removal.

When pin 16 is lodged in position as described the "pin locks the crank and bearing together.

merals 1, 2, 3, 4 and 5. The apertures 20 and grooves I4 may be greater or fewer in number as may be desired. The numerals, for example, indicate that when pin I6 is located in aperture 20 designated as 1 and the axially aligned aperture formed by a groove I4 and groove I5, then the connecting rod I rotates feed screw 6 at a stroke ieeding 10 pounds of coal from hopper I to the furnace in one hour. If pin I6 is located in the aperture designated with the numeral 5, and the axially aligned aperture formed by a groove I4 and groove It in registry, then the feed screw is rotated, for example, to feed fifty pounds of coal in one hour fromthe hopper to thefurnace.

Dial plate I1 is provided primarily for the purpose of rotating the bearing race, I3 of bearing I2 to the feed position and for designation of rates of coal feed thereon that may be radially observed by the operator. The operator grasps plate I1 and rotates the same to rotate bearing .race I3 therewith so that a groove I4 of the race will register with the notch I5 of the crank to give the coal feed desired and as indicated on the cover plate IT with the numerals as described. ..Plate I! is constructed with vertical indentations 23 for insertion of a suitable tool by the operator should that be necessary to rotate the plate. and bearing race I3, r

The center of bearing I2, as previously described, is eccentric to the center of crank II which also is eccentric to the center of transmission shaft ID. By adjusting the center of bearing I2 ,to differentlocations radially about the center of crank II by operation ofdial plate H, the radial distance between the center of .bearing I2 and the center of transmission shaft I is varied to determine the length of the stroke of connecting rod I. This results in diiferent rates of feed of screw ,6.

Figs. 4, and 6 illustrate three rates of feed. In Fig. 4 bearing race I3 has been rotated by movement of dial plate I I so that pin I6 can be inserted throu h he pe t f r by registry of crank groove with a groove I4 of of coal.

Fig. 5 illustrates an intermediate rate of coal feed under which pin I6 extends through the aperture designated with the numeral 3 on dial plate I1 and is disposed in the aperture formed by registry of a groove I4 of bearing race I3 and groove I5 of crank II to lock the bearing race and crank together for rotation.

Fig. 6 illustrates the greatest feed of coal. In Fig. 6 bearing race I3 has been rotated by move- 'ment of dial plate all so that pin I6 can be inserted through the aperture designated with the numeral 5 and into the aperture formed by registry of crank groove I5 with a groove I4 of race I3. Since at this position of the center of bearing I2, under the setup shown in the drawings, the radial distance is the greatest between the center of shaft I0 and the center of bearing I2, the throw of the crank in the bearing actuates connecting rod I in its longest stroke and the rod rotates screw 6 in the greatest amount of feed. a

By employing the double eccentric arrangement described and varying the relationship of the two eccentrics to determine the radius of the crank movement applicant provides a novel mechanism for varying the feed rates of a stoker.

Various embodiments of the invention may be employed within the scope of the accompanying claim.

I claim: 7

An eccentric for adjusting the length of stroke .of a member connected at one end to a driven shaft and at the other end to a power driven transmission shaft to rotate the driven shaft therefrom, which comprises a crank extending axially from said transmission shaft in eccentric relation thereto and having a relatively short shaft extending axially therefrom, a bearing secured within the transmission end of said connecting member and having an oifset crank opening in the inner race thereof to receive said crank and dispose the center of the bearing ,eccentric to the center of said crank, said inner-race of the bearing having a plurality .of semi-circular grooves extending longitudinally through the bearing surface thereof and circumferentially spaced from each other to dispose the same at different radial distances from the center of. the bearing, a longitudinally extending groove pro vided in the outer periphery of said'crank and formed complementary to the grooves in the bearing race, a'plate assembled over said short shaft of the crank and secured to said bearing for rotating the same to. locate difierent ,grOo es in the bearing race in registry with the crank groove and with apertures through the plate axially aligned with the grooves in the bearing race, a removable pin extending through an aperture in the plate and'disposed in the aperture formed by registering a groove of the bearing race with the groove of the crank to lock the crank and bearing race together for rotation for different throws of the crank, and a lock pin extending through the removable pin and short shaft of the crank to lock the removable pin against axial movement.-

PI-llLIP C. MALMS'I'EN.

REFERENCES CITED The following references are of record in the file of this patent: 1

UNITED STATES PATENTS 

